Regulating system



July 7, 1936. H. c. NYCUM REGULATING SYSTEM Filed March 8, 1955WITNESSES: INVENTOR Patented July 7, 1936 BEGULATING SYSTEM Homer C.Nycum, Wilkinsburg,'Pa., assignor to Westinghouse Electric &Manuiacturing Company, East Pittsburgh, Pa., a corporation ofPennsylvania Application March 8, 1935, Serial No. 9,967 3 Claims. (01.171-312) My invention relates to electrical regulating systems, and ithas particular relation to rheostatic type generator voltage regulatorswherein a separate quick-acting contact-making device sensitive to largechanges in the regulated voltage is utilized to control a pair offield-forcing contactors.

In systems of this and other equivalent classes, the mentionedfield-forcing control equipment supplements the major contact-mak-- ingvoltmeter which by controlling the motoroperated rheostat effectsnormally-required corrective adjustments in the'machine excitation. Bothof these contact-making devices are energized by a measure of theregulated .voltage or other quantity to be maintained constant.

The major or normal-voltage-controlling contact-making device isprovided with a voltageadjusting rheostat or other calibration-adjustingmeans connected in circuit with its actuating winding. In order toassure proper correlation between the quick-acting contact-making deviceand the one just referred to for diflering settings of thiscalibration-adjustor, it is essential that the quick-acting device alsobe subjected to changes in its calibration which correspond to those ofthe normal device originally operated on. a

Generally stated, the object of my invention is to provide means forautomatically adjusting the calibration of the quick-response device indirect correspondence with calibration changes in the normal-responsequantity-sensitive device.

Another object of my invention is to provide a system of this type whichtakes into account any difference in the characteristics of the twoquantity-sensitive devices correlated and their calibration-adjustingmeans.

In practicingmy invention, I connect in the energizing circuit of thequick-response device a calibration-adjustingtrheostat adapted to beoperated bya reversible motor. I'then equip the movable member of thisdevice with a resilient connection through which a set of auxiliarycontact members, sensitive to relatively small changes in the regulatedquantity, are actuated. By utilizing these contact members to controlthe operation of the calibration-adjusting motor betore-mentioned, I amable at all times to maintain the calibration'oi the quick-responsedevice in proper correlation with that of the normal change-responsedevice throughout its entire range of calibration adjustment.

My invention itseli', together with additional objects andadvantages-"thereof, will best be understood through the followingdescription of a specific embodiment, when taken in conjunction with theaccompanying drawing, in

.which the single figure is a diagrammatic representation of apparatusand circuits showing the 5 calibration correlating means of my inventionapplied to a rheostatic type of generator voltage regulator.

Referring to-the drawing, the regulating System there depicted isadapted to maintain con- 10 stant the voltage of an electrical generatorill, the armature windings of whichare directly connected with theconductors of an output circuit l2, and the field winding ll of whichderives energy from the armature winding of a direct-current exciter IS.The field winding 18 of this exciter is shown as deriving itsenergization from a source of substantially constantdirect-currentpotential represented by circuit conductors 20.

Adjustment of the current supplied to winding I8 is effected by arheostat 22 which is equipped with a reversible operating motor, 24, theenergization of which, in the generator voltage raising and loweringdirections, respectively, is 95 controlled by a pair of relays R and L.Selective actuation of these two relays is effected by means of acontact-making voltmeter 26, the actuating winding 28 of which isenergized by a measure of the voltage, supplied by the regu- 3 latedgenerator in to circuit i2, through a con-' nection which includes atransformer 30.

In operation of the basic regulating system thus fardescribed, as longas thetvoltage oi circult l2 remains of the value desired, the movable 3contact member 32 of the device 28 occupies the neutral or mid-positionillustrated, and neither relay R nor L is actuated. li'or such acondition, the upwardly acting magnetic pull exerted'by winding 28 01.device 28 upon the 40 ,contact-carrylngarm 34 just balances'the opposingdownward pull of a tension spring 36.

In the event that the voltage of circuit l2 falls below the desiredvalue, spring 38 biases contact member 32 downwardly into engagementwith a stationary member 1', and thereby completes anactuating circuitfor motor control relay B. This circuit, as do all of the remaining Ycontrol circuits represented, receives e'nergization from thecontrol-source conductors ,20. 50

Thus actuated relay R biases its contact mem-; bers upwardly, completingthrough member 38, an energizing circuit which causes rheostat opcratingmotor 24 to run in a direction which decreases the resistance ofrheostat andfby.

raising. the current supplied to exciter fleld winding l8, efiects acorrective adjustment in the voltage of regulated machine It).

In a similar manner, in the event that the regulated voltage rises abovethe desired value, device 26 biases its contact member 32 upwardly intoengagement with a stationary member 1. This completes an actuatingcircuit for motor control relay L which, in biasing its contact member46 upwardly, completes a circuit from control source 26 for energizingmotor 24 in a direction to raise the resistance of rheostat 22 tothereby correctively efiect a lowering of the voltage of regulatedmachine II).

In the majority of installations of such rheostati voltage regulatingsystems, it is desirable to supplement the equiment just detailed, whichin itself is capableof effecting the corrections in regulated quantityat a relatively slow rate only, by quick-response apparatus whichcomesinto action only when the regulated quantity deviates from its desiredvalue by a large amount. Such supplemental equipment conventionally maytake the form of a pair of field-forcing relays R. and L, which whenactuated, respectively short-circuit the rheostat 22 to effect a rapidincrease in the current supplied to the exciter field winding l8, andinterrupt a normally maintained shunt connection around a resistor 42,which causes the current supplied to the exciter field winding torapidly decrease. The two. actions just named are effected by means ofcontact members 44 and 46, respectivelmassociated with the two relays Rand L.

To selectively control the actuation of these two relays, it iscustomary to provide a second contact-making device 48, the contacts ofwhich close only upon predeterminedly large deviations in the voltage'ofregulated circuit I2. As shown, this device comprises an actuatingwinding 56 which is parallel-connected, between conductors 52 and 54which comprise the output circuit of the regulated-voltage energizedtransformer 30, with winding 28 of the normally responsive element 26. Amovable contact member 56 of device 48 is adapted to engage one or theother of the two cooperating stationary members 1" and 1' only when thevoltage of regulated circuit l2 deviates by a large amount, such as 5%or more, from its desired value. The sensitivity of device 48 is thusmuch lower than that of the major contact-making device 26 which in aconventional installation may engage its contact members upon regulatedquantity deviations no greater than A: of 1%.

In operation of these quick-response quantity corrective means, when thevoltage of regulated circuit I2, for example, drops below its desiredvalue by the 5% or other predeterminedly large amount to which device 48is sensitive, the tension spring 58 of this, device overcomes theupwardly acting pull of the actuating winding 50 and thus biases contactmember 56 downwardly into engagement with stationary member r'. Thiscompletes, from control source 20, an actuating circuit for excitation,raising relay R which, by biasing contact member 44 upwardly, theneffects, in the manner before explained, a rapid rise in the voltage ofregulated machine [0. As soon as the correction brings the voltage errorbelow the value to which contact-making device 48 is sensitive, contactmember 66 thereof disengages from member 1" and by allowing relay R toreturn to the unactuated position illustrated, restores control to thenoraccordance with my invention, I provide means for automaticallyaccomplishing this function.

trolled by an auxiliary set of contact members 7 mally-responsivevoltage sensitive device 26 and the motor-operated rheostat 22.

In a similar manner, in the event that thr voltage, of regulated circuitl2 risesabove its desired value by, say, 5% or other predeter- 5 minedlylarge amount, device 48 biases its contact member 56 upwardly intoengagement with stationary member Z to complete an actuating circuit forexcitation-decreasing relay L. In moving contact member 46 thereofupwardly, this relay inserts into the energizing circuit of exciterfield winding l8 the resistor 42 which, as already explained, rapidlydecreases the voltage of regulated machine l0. Contacts 56 and l ofdevice 48 reopen when this voltage again apl5 proaches the desiredvalue, and thereby restores control to the basic contact-making device26 and. the motor-operated rheostat 22.

In order to prevent hunting of the contactmaking device 26, it is usualto provide in the energizing circuit thereof a pair of resistors such asare shown at 60 and 62, which serve to sufficiently modify thecalibration of the relay upon the respective actuation of motor controlrelays R and L as to effect a disengagement of the movable contactmembers 32 of device 26 slightly beforethe voltage of circuit l2 has,after a deviation, been completely brought back to the desired value.

In any regulating system, it is desirable to 30 adjust the magnitude ofthe quantity being maintained constant either to match changingoperating conditions, or for other reasons. In a system of the typedisclosed, this adjustment is conveniently effected through the use of arheostat 64 connected in the energizing circuit of the actuating winding28 of the contact-making device. By changing the position along theresistor of the movable contact member 66, the value of the voltage ofcircuit I2, at which the movable contact member 32 of the device willoccupy the mid or neutral position shown, may be varied throughout asubstantial range. Thus, as the resistance of rheostat 64 is decreased,as by moving the adjusting contact 66 downwardly, a lower voltage ofcircuit l2 will suflice to maintain relay 26 in its neutral orcontact-disengaged position. Similarly, as the resistance of thecalibration-adjusting rheostat is increased, as by moving contact 66upwardly, a higher voltage in the regulated circuit I2 is necessary tomaintain the contact 32 in the illustrated disengaged position.

In order that the quick-response large changesensitive device 48 may, atall times, properly correlate its operation with that of the basiccontact-making device 26, it is essential, as before explained, that itscalibration should, in a general way at least, bechanged or adjusted inthe same manner as is that of device 26. In

I In the diagram, these means are illustrated as comprising a secondcalibrating-adjusting rheostat 68 connected in the energizing circuitfor the actuating winding 50 of device 48. This rheostat is providedwith a reversible operating motor III, the energization of which isconl|2--r", which are actuated by the quickresponse device 48.Preferably, the sensitivity of these auxiliary members is much higherthan that of the main members l'-56r' of device 48 and in degree mayeven approach the high 7 sensitivity of the normally-responsive device26. Thus, in a practical installation, a sensitivity of the generalorder of 1% or 2% regulated-quantity deviation is found to be mostsatisfactory.

In one form of mounting found to be suitable, the movable member 12 ofthis auxiliary contact set may be carried by a resilient extension" ofthe main contact carrying arm 16. When so arranged, the earlierengagement oi member 12 with one of its cooperating stationary membersdoes not prevent such further movement of the arm; as may be necessaryto engage the main contact member 56 ,of device 48 with one or theother. of its two cooperating stationary members.

In operation of the calibration-matching equipment'just described, thenamed auxiliary device 26 is raised, as by moving contact member 88upwardly along resistor 64, a higher voltage will be maintained betweenconductors 52 and 54 with the result that quick-responsive device 48,energized therefrom, will bias contact member i2 upwardly intoengagement with member I", and thereby complete for motor it anenergizing circuit which effects operation of rheostat 88 in theresistance-increasing direction.

The circuit just completed may be traced from the upper of controlsource conductors 2% through conductor 88, the armature 8i and the fieldwinding 82 of motor i8, conductor 83, the contact members Z" and 12 ofdevice 58 and conductor 84 back to the lower of control sourceconductors 28. Adjustment continues until the voltage supplied towinding 58 of device 18 is reduced to a value closely comparable to thatsupplied to Winding 28 of device 28, at which time disengagement ofcontact members it and l," is effected.

In a similar manner, in the event that calibration-adjusting rheostat 84is adjusted in the resistance-decreasing direction to lower thecalibration of device 26, the voltage appearing between conductors 52and 54 is correspondingly reduced by action of device 26 andquickresponse device 48 energized thereby moves contact member 12downwardly into engagement with member 1"", thereby completing a circuitwhich energizes motor T8 in a direction to similarly decrease theresistance of the calibrationadjusting rheostat 68 and thereby bringdevice 48 to the same calibration as is the major device This circuitmay be traced from the upper of control-source conductor 20, throughconductor 80, the armature and field windings 8| and 86 of motor '70,conductor 81, the contact members r" and 12 of device 48, and conductor84 back to the lower of control source conductor 20. Adjustmentcontinues until the voltage supplied to winding 50 of device 48 isreduced to" a value closely comparable to that supplied to winding 28 ofdevice 26, at which time disengagement of contact members is efiected.

Although I have shown and described a certain specific embodiment of myinvention, I am fully aware that many modifications thereof arepossible. My invention, therefore, is not to be restricted exceptinsofar as is necessitated by the prior art and by the scope of theappended claims.

I claim as my invention:

1. In a regulating system comprising slow response quantity-adjustingmeans, a contactmaking device sensitive to small changes in theregulated quantity for controlling said means, calibration-adjustingmeans for said device, quick response quantity-adjusting means, and asecond contact-making device sensitive to larger changes in theregulated quantity for controlling said quick-response means, thecombination of means for matching the calibration of said second-namedcontact-making device with that of the one first named comprisingcalibrationadjusting means for the second named device, and a second setof contact members actuated by said device in a manner to respond tosmall changes in the regulated quantity and adapted to control theoperation of said second-named caiibratiomadjusting means.

2'. In a regulating system comprising both slow-acting and quick-actingquantity adjusting means, a contact-making device adapted to control theoperation of said slow-acting means in response to small errors in theregulated quantity, a second contact-making device adapted to controlthe quiclcacting means in response to larger errors, and separatecalibration-adjusting means for each of said contact-making devices, thecombination with the calibration-adjusting means of the large-errorsensitive device of operation-control means therefor so actuated by the"device as to cause the said adjusting means to follow adjustments ofthe small-error responsive device ca ibration-adjusting means.

3. In a regulating system comprising both slow-acting and quick-actingquantity-adjusting means, a contact-making device adapted to control theoperation of said slow-acting means in 50 response to small errors inthe regulated quancity, a second contact-making device adapted tocontrol the quick-acting means in response to larger errors, andseparate calibration-adjusting means for each of said contact-makingdevices, the combination with the calibrationadjusting means of thelarge-error sensitive device of operation-control means therefor,including a second set of device contact members, so 60 actuated by thedevice as to cause said adjusting means to follow adjustments of thesmallerror-responsive device calibration-adjusting means.

HOMER o. NYCUM.

